			// 三个参数 1.所有要加载的图片的对象  2. 加载进度函数  3.加载完成函数
			function loading(imgsObj,handleObj){
				// 遍历对象，得到对象中属性的个数，即有多少图片
				var count = 0;
				var currentIndex = 0;
				for (prop in imgsObj) {
					count++;
				}
				// 图片全部完成加载之后传出的对象
				var imgObj = {};
				for (prop in imgsObj) {
					var img = new Image();
					img.src = imgsObj[prop];
					
					img.onload = (function(prop){
						return function(){
							currentIndex++;
							var scale = currentIndex/count*100;
							if (handleObj.progress) {
								handleObj.progress(scale);
							}
							imgObj[prop] = this;
							if (currentIndex == count) {
								handleObj.complete(imgObj);
							}
						}
					})(prop);
				}
			}
